Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gmi

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "\\b(?:(?:[A-Z][A-HJ-Y]?[0-9][0-9A-Z]?|ASCN|STHL|TDCU|BBND|[BFS]IQ{2}|GX11|PCRN|TKCA) ?[0-9][A-Z]{2}|GIR ?0A{2}|SAN ?TA1|AI-?[0-9]{4}|BFPO[ -]?[0-9]{2,3}|MSR[ -]?1(?:1[12]|[23][135])0|VG[ -]?11[1-6]0|[A-Z]{2} ? [0-9]{2}|KY[1-3][ -]?[0-2][0-9]{3})\\b"; final String string = "M1 1AA\n" + "M60 1NW\n" + "CR2 6XH\n" + "DN55 1PT\n" + "GY101ZZ\n" + "W1A 1HQ\n" + "EC1A 1BB\n" + "CW3 9SS\n" + "SE5 0EG\n" + "SE50EG\n" + "se5 0eg\n" + "WC2H 7LT\n" + "BS98 1TL\n" + "BX1 1LT\n" + "BX2 1LB\n" + "BX3 2BB\n" + "BX4 7SB\n" + "BX5 5AT\n" + "CF10 1BH\n" + "CF99 1NA\n" + "CV4 8UW\n" + "CV35 0DB\n" + "DA1 1RT\n" + "DE99 3GG\n" + "DE55 4SW\n" + "DH98 1BT\n" + "DH99 1NS\n" + "E14 5HQ\n" + "E14 5JP\n" + "E16 1XL\n" + "E20 2AQ\n" + "E20 2BB\n" + "E20 2ST\n" + "E20 3BS\n" + "E20 3EL\n" + "E20 3ET\n" + "E20 3HB\n" + "E20 3HY\n" + "E98 1SN\n" + "E98 1ST\n" + "E98 1TT\n" + "EC2N 2DB\n" + "EC4Y 0HQ\n" + "EH12 1HQ\n" + "EH99 1SP\n" + "G58 1SB\n" + "GIR 0AA\n" + "IV21 2LR\n" + "L30 4GB\n" + "LS98 1FD\n" + "M50 2BH\n" + "M50 2QH\n" + "N1 9GU\n" + "N81 1ER\n" + "NE1 4ST\n" + "NG80 1EH\n" + "NG80 1LH\n" + "NG80 1RH\n" + "NG80 1TH\n" + "MSR1110\n" + "MSR1120\n" + "MSR1210\n" + "MSR1230\n" + "MSR1250\n" + "MSR1310\n" + "MSR1330\n" + "MSR1350\n" + "PH1 5RB\n" + "PH1 2SJ\n" + "S2 4SU\n" + "S6 1SW\n" + "SB 01\n" + "VG1110\n" + "S14 7UP\n" + "SE1 0NE\n" + "SE1 8UJ\n" + "SM6 0HB\n" + "SN38 1NW\n" + "SR5 1SU\n" + "SW1A 0AA\n" + "WC1N2PL\n" + "SW1A 0PW\n" + "SW1A 1AA\n" + "SW1A 2AA\n" + "SW1A 2AB\n" + "SW1H 0TL\n" + "SW1P 3EU\n" + "SW1W 0DT\n" + "TW8 9GS\n" + "W1A 1AA\n" + "W1D 4FA\n" + "W1N 4DJ\n" + "W1T 1FB\n" + "CO4 3SQ\n" + "SAN TA1\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.CASE_INSENSITIVE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html